1. Field of the Invention
The invention relates to a drill supporting apparatus, in particular an apparatus for supporting a diamond drill head and a feed frame associated therewith.
2. Prior Art
Diamond drills have been used for many years for geological exploration and test drilling. Some types are powered by a machine having a drill head containing a screw feed mechanism, whilst other types utilize a powered head carried on a hydraulic feed unit. Either type may be attached to a skid or a bar mount which is secured adjacent to a rock surface at a drill station. Positioning and securing the machine in relation to the axis of the hole to be drilled can be difficult and time consuming, and failure to anchor the machine securely can result in misalignment problems which reduce machine performance and increase wear on drill rods etc., with consequent loss of drilling time and high maintenance costs.
When drilling in a confined space underground, the space available to insert drill rods into, or to withdraw drill rods from, a hole may be critical and is referred to as `tail room`. If tail room can be increased, longer sections of rods can be removed or replaced with an accompanying saving of time. In some machines the drill head can be swung clear of the hole axis, thus increasing the tail room, and then a pulling dog can be fitted and aligned with the hole to remove or replace rods. The pulling dog is fed by an external air cylinder, winch means or sometimes the drill feed mechanism. It is known that conventional hydraulic feed mechanisms have feed speeds adequate only for actual drilling and are too slow for removing or replacing rods, particularly in deep holes. Each has its particular advantages but no device known to the inventors functions adequately and safely for all angles of bore holes.
Operation of diamond drilling machines can involve hazards; for instance when drilling upwards, the weight of the string of drill rods and the weight of water within the rods must be supported by the drill head chuck, or a drill rod locking device when the chuck is released. With some drill heads and drill rod locking devices, accidental loss of hydraulic pressure releases the chuck or rod lock gripping force, which can result in extreme danger to operators.